static const float4 palette[16] = {
    float4(0x00 * 255 / 63, 0x00 * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x00 * 255 / 63, 0x2e * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x2e * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x2e * 255 / 63, 0x2e * 255 / 63, 0xff) / 0xff,
    float4(0x2e * 255 / 63, 0x00 * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x2e * 255 / 63, 0x00 * 255 / 63, 0x2e * 255 / 63, 0xff) / 0xff,
    float4(0x2e * 255 / 63, 0x1d * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x2e * 255 / 63, 0x2e * 255 / 63, 0x2e * 255 / 63, 0xff) / 0xff,
    float4(0x1d * 255 / 63, 0x1d * 255 / 63, 0x1d * 255 / 63, 0xff) / 0xff,
    float4(0x1d * 255 / 63, 0x1d * 255 / 63, 0x3f * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x3f * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x3f * 255 / 63, 0x3f * 255 / 63, 0xff) / 0xff,
    float4(0x3f * 255 / 63, 0x22 * 255 / 63, 0x22 * 255 / 63, 0xff) / 0xff,
    float4(0x3f * 255 / 63, 0x00 * 255 / 63, 0x3f * 255 / 63, 0xff) / 0xff,
    float4(0x3f * 255 / 63, 0x3f * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x3f * 255 / 63, 0x3f * 255 / 63, 0x3f * 255 / 63, 0xff) / 0xff,
};
